Improving the accuracy of the diffusion model in highly absorbing media.

Cong AX, Shen H, Cong W, Wang G - Int J Biomed Imaging (2007)

Bottom Line:
It produces satisfactory results in weakly absorbing and highly scattering media, but the accuracy lessens with the decreasing albedo.The diffusion model behaves more closely to the physical model with the actual optical parameters substituted by the optimized optical parameters.The effectiveness of the proposed technique was demonstrated by the numerical experiments using the Monte Carlo simulation data as measurements.

ABSTRACTThe diffusion approximation of the Boltzmann transport equation is most commonly used for describing the photon propagation in turbid media. It produces satisfactory results in weakly absorbing and highly scattering media, but the accuracy lessens with the decreasing albedo. In this paper, we presented a method to improve the accuracy of the diffusion model in strongly absorbing media by adjusting the optical parameters. Genetic algorithm-based optimization tool is used to find the optimal optical parameters. The diffusion model behaves more closely to the physical model with the actual optical parameters substituted by the optimized optical parameters. The effectiveness of the proposed technique was demonstrated by the numerical experiments using the Monte Carlo simulation data as measurements.

fig2: The comparison between solutions of DA using the theunadjusted and the optimal optical parameters in a medium with mm−1 and mm−1. The light source was 1 mm from the origin. (a) Solution of DA with unadjusted optical parameters versus MC data. (b) Solution of DA with optimized optical parameters versus MC data. The detector positions were sorted in the increasingorder of the fluence rate of MC data.

Mentions:
Using the optimized parameters in Table 2, the results of the accuracy improvementsof DA are plotted in Figures 2 and 3, with respect to the two media.

fig2: The comparison between solutions of DA using the theunadjusted and the optimal optical parameters in a medium with mm−1 and mm−1. The light source was 1 mm from the origin. (a) Solution of DA with unadjusted optical parameters versus MC data. (b) Solution of DA with optimized optical parameters versus MC data. The detector positions were sorted in the increasingorder of the fluence rate of MC data.

Mentions:
Using the optimized parameters in Table 2, the results of the accuracy improvementsof DA are plotted in Figures 2 and 3, with respect to the two media.

Bottom Line:
It produces satisfactory results in weakly absorbing and highly scattering media, but the accuracy lessens with the decreasing albedo.The diffusion model behaves more closely to the physical model with the actual optical parameters substituted by the optimized optical parameters.The effectiveness of the proposed technique was demonstrated by the numerical experiments using the Monte Carlo simulation data as measurements.

ABSTRACTThe diffusion approximation of the Boltzmann transport equation is most commonly used for describing the photon propagation in turbid media. It produces satisfactory results in weakly absorbing and highly scattering media, but the accuracy lessens with the decreasing albedo. In this paper, we presented a method to improve the accuracy of the diffusion model in strongly absorbing media by adjusting the optical parameters. Genetic algorithm-based optimization tool is used to find the optimal optical parameters. The diffusion model behaves more closely to the physical model with the actual optical parameters substituted by the optimized optical parameters. The effectiveness of the proposed technique was demonstrated by the numerical experiments using the Monte Carlo simulation data as measurements.